Carbon for incandescent electric light



(No Model.)

N. s. WHITE. GARBONFOR INGANDBSGENT ELECTRIC LIGHTS. No. 301,192. Patented July 1, 1884.

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WITNEEEEE v I INVENTEIR Z604 /0. m

UNITED diar es PATIENT .Urrict;

NELSON S. \VI'IITE, OF CANTON, MASSACHUSETTS.

CARBON FDR INCANDESCENT ELECTRIC LEGHT,

SPECIFICATION forming part of Letters Patent No. 301,192, dated July 1, 188

Application filed March 10, 1884.

To all whom it may concern.-

Be it known that I, Nansen S. WHIT of Canton, in the county of Norfolk and State of a Massachusetts, a citizen of the United States, have invented a new and useful Improvement in Oarbons for Incandescent Electric Lights, of which the following is a full, clear, and exact description, reference being had to the accom-- panyin g drawings, forming a part of this spccification, in which- Figure 1 represents in elevation an incandescent electric light containing my invention. Figs. 2, 3, 4: and 5 are detail views, hereinafter more especially referred to.

- The invention relates to a carbon especially adapted for use in incandescent electric lights, and comprises a carbon filament which supports or carries upon its surface patches or particles of metal or other similar substance, adapted, when heated by the carbon, to diffuse light. I prefer to use a filament of carbon that shall follow very nearly the curve of the globe or bulb thus formed, and be very nearly equidistant from the globe or bulb throughout its length, in order to obtain a better dissemination of the light; and in the drawings Z1 represents this carbon filament. I prefer to make it of fiber, and to fill the interstices, and cover or partially cover the surface of the fiber with metal particles, which shall be heated by the carbon, as I find by so doing that I obtain two important results: First, by using a metal which can be heated to a white heat at a low temperature I am enabled by a comparatively slight expenditure of electro-motive force to obtain a very white and intense light, much resembling that of an are light; and, second, I am enabled to obtain a very brilliant and powerful light.

The first advantage relates to the obtaining of a light by a much weaker current than is now generally employed, thereby enabling me to burn or use more lights with a given strength of electrical current than is now possible; and the second advantage relates especially to the brilliancy' of the light, which is very marked, even when a much weaker current is employed. I may use for the purpose silver, brass, iron, zinc, lead, tin, or any other suitable metal or alloy or combination of metals;

but I prefer to use the metals which show a white heat at a comparatively low tempera- (No model.)

turesuch, for instance, as silver, tin, zinc, or copper. This metal of course must be disseminated or arranged in or upon the carbon so as not to make a continuous metal connection between the ends of the platinum wire, in order that the carbon mayact to cause the necessary resistance to the current to become sufficiently hot to heat the metal particles. I prefer to make the carbon of silk, flair, cotton, or linen fiber or thread; but of course I do not wish to be understood as confining myself thereto.

On some accounts I prefer to use silver as the metal to be united with the fiber; but, as above stated, I do not confine myself thereto. IVhen silver is used, it is treated with an ammoniacal solution formed by dissolving nitrate of silver in water, then precipitating the same with ammonia, and then adding to the precipitate sufficient ammonia to dissolve it. Into this solution the fiber is placed and allowed to soak therein for from two to ten or twelve hours, when it becomes largely covered and saturated with an ammoniacal oxide of silver. The fiber thus treated is stretched and dried, then coatedwith an adhesive solution, and covered with fine plumbago or gashouse-retort carbon, or a mixture of both, which is well rubbed in thereto, and is held thereon by the adhesive solution. It is then cut into suitable lengths for the carbon filament, and is placed in grooves cut in a carbon plate and covered with a thin layer of plumbago or gas-l1ouse-retort carbon, or a mixture of bot-h, and is then carbonized in a muffle. After carbonization the carbon filaments are placed in the silver solution and allowed to remain therein from three to eight hours. This fills the interstices and covers the sun face of the carbon with silver, so that it may be said that the carbon is charged on its surface with the silver. Each carbon is then placed in avacuum and a current of electricity passed through it. It is then taken out and,

in some instances, heated again, when it is ready for use. \Vhen other metals are used, theearbon and the fiber preferably are metallized by substantially the process herein described-that is, by soaking in the solution of the meta1-altheugh I do not confine myself to this method of intimately combining the carbon and the metal.

The carbon thus made may be styled a metallized carbon, in that the surface of the carbon is impregnated, and its interstices filled to a greater or less extent with metal. This metallized carbon requires resistance sufficiently high to cause the metal to glow at a White heat.

To connect the carbon with the platinum wire, I prefer to employ a joint, substantially as shown in Figs. 1, 2, 3, 4, and 5that is, I form upon-each end of the platinum wire a the tube Through these tubes I pass the ends 0 of the carbon, which are bent on the platinum wire, as represented in Fig. 3. I then connect the wire with the carbon by a cement composed, substantially, of the following elements: plumbago, forty parts; gas-house car'- bon, thirty-five parts; clay, twenty parts; bo-

rax, four parts; sal-ammoniac, one part. The clay and sal-ammoniac are placed in a copper pan and heated to a red heat, fused and pulverized when cold, and are then mixed with the other-ingredients and with water. The cement thus prepared is applied with a brush about the joint, (see 6, Figs. 1 and 4,)

and then placed in a gas-jet and heated until red hot, when it is permitted to cool. The

cement should entirely cover the joint, and

extend well on the platinum wire.

Of course, in the metallized carbon herein described, I do not confine myself to the use of one particular metal, but may use a combination of metals or alloy, if desired. Neither I do not claim herein the joint, form of the glass globe and of the carbon, and the manner of attaching the reflector and gage to the lamp, as these features are to be included in an application which I am about to make.

I am aware of the Patent No. 259,062, dated I June 6, 1882, granted 0. J. Van Depoeld, and.

also Patent No. 194,563, dated August 28, 1877, granted to W. E. Sawyer; but as they do not describe a carbon treated and prepared and having the properties and advantages of the carbon herein described, I consider that they do not embrace the essential features of my invention. 1

I am also aware that metal filings mixed with carbon adapted for burning in the open air in arc lights have been used; but I consider that they do not contain the essential features of my invention, because I do not consume my m'etalliz'ed carbon, but simply heat the same to a heat in a vacuum to a temperature sufficient to diffuse light.

Having thus fully described my invention, I claim as new and desire to secure by Letters Patent of the United States 1. A carbon filament for incandescent electric lights, coated with metal particles, sub stantially as described.

2. In a filament for incandescent lights, a body of carbon carrying upon its surface particles of metal adapted to be heated thereby, substantially as described.

NELSON s. WHITE.

Witnesses:

F. F. RAYMOND, 2d, ,FRED', HARRIS. 

